Tire age is an essential aspect when it comes to how effective a set of tires might be. Even though you did not use them, it still does not mean that they are “as new”. Most people rely on the trusted “Penny Test” to determine how old a tire is, but this only makes sense if the tires were in constant use.
When Is A Tire Too Old To Sell?
It depends on if the tire has been used or not. Many experts state that you should not use or sell tires if they are more than 3-4 years old and were in constant use prior to that. If you have a set of unused tires laying around, you should not use or sell them if they are more than 6-8 years old, and that only makes sense if they were stored properly beforehand.
Climate is also an important factor as extreme conditions such as constant heat can make the tires unusable after only a year or two. Improper storage can also make your tires deteriorate even faster. All in all, be sure not to sell or use your tires if they are experiencing visible tire deformations such as sidewall damage, bubbles or flat spots.
What Causes Tires To Age Quickly?
- Oxygen levels
- UV light
- Temperature and Humidity
Believe it or not, oxygen is the main culprit when it comes to tire deterioration as it breaks down the tire compound both from inside and out. Even though all modern-day tires utilize various antioxidant blends in tire construction, these can only slow down the rate at which the tire deteriorates.
The polymer structure eventually starts losing the battle against oxygen and that is when a tire starts breaking down at a faster rate.
A process called photodegradation happens when the tire sits in direct sunlight for a while as the polymer structure that makes the tire starts to decay. Tires absorb UV light the moment they are exposed to it which means that the tire slowly starts disintegrating.
Tire manufacturers try to negate this with a so-called carbon black finish which is able to absorb that light and turn it into heat. However, these protective properties lose their effectiveness over time and your tires literally start “feeling the heat”.
Ozone is essentially oxygen with an additional atom strapped onto it. Most of us heard about it because it can be found in the troposphere and the stratosphere, yet ozone is also constantly being created thanks to manmade pollution and is fairly detrimental to tire longevity, especially if the tires are not used.
Back in the 1950s scientists discovered that ozone plays a huge role when it comes to tire degradation and many tire manufacturers neutralize these effects by employing special wax and oil compounds directly onto the tire. However, these are virtually ineffective when it comes to stored tires.
Temperature And Humidity
Temperature and humidity are a really bad combination for stored tires as these can significantly shorten the lifespan of a tire. Heat causes thermo-oxidative tire degradation while humidity opens the door for ozone-induced degradation as well.
As such, be sure to store your tires in an environment that is preferably between 32 F and 72 F, and always try to store them away from any potential sources of humidity.
How To Determine The Age Of A Tire?
Tires made in the 21st century usually come with a four-digit code placed directly on the sidewall of the tire. The code looks something like this – 0317 and is being accompanied by the DOT (Department of Transportation) number and the entire sequence tends to look something like this – DOT ATE9 UA40 0317.
The first two numbers (03) represent the week in which the tire has been made while the second two numbers (17) represent the year, which in this case is 2017. This means that a tire that carries the 0317 four-digit code was made in the 13th week of 2017.
Pre 2000 tires come with a three-digit code which means that they are more than 22 years old at the time of making this article. It is a bit trickier to determine how old a three-digit code tire can be, but it is for certain that it is way too old for any purpose besides a tire graveyard.
Are Tire Shops Legally Allowed To Sell Old Tires?
There are no specific laws that prevent tire shops from selling you a set of old tires. The only way to make sure is to inspect the four-digit code on the tire. Some tire shops have a strict policy on older tires which means that they are not only going to refuse to sell you a set of older tires, they might even refuse to mount them on your car.
How Long Do Most Tire Warranties Last?
Most tire manufacturers offer a 4-6 year tire warranty while some manufacturers will even cover their tires for 8-10 years or until the tread wears out. Obviously, driving with a set of bald tires is always a bad idea, and no one is willing to cover any potential damages that might arise from a set of bald tires.
This means that they are not 100% confident that their tires will indeed last 4-6 years long. Many different aspects influence how long a tire can last and it is rather impossible to perfectly gauge the true lifespan of a tire. However, there are ways how one can make a tire last longer.
If you want to sell tires that have been in constant use, be sure to do so before they reach their 4th or 5th birthday, and only if the tire is in good overall condition. However, if you have a set of stored tires lying around, you should not sell them after 6-8 years in proper storage.
Many different factors play a role in how long a tire can last and still be considered safe. It makes no sense to buy a set of well-used tires anyway because tires are an essential safety aspect. It is virtually impossible to ever emphasize the importance of tires as they are the only thing that connects the car to the road.